Drawtwisting machinery



Nov. 21, 1961 E. BROMLEY ET AL 3,009,308

DRAWTWISTING MACHINERY Filed March 10, 1960 /4 ALTEIPIVATUR DRAM/50X ALTERNATOR 4 AL 759M470? INVENTORS 1 Jalzwslfbmmlqlfid Raymund afiallklllirz/ WZZM United States Patent Delaware Filed Mar. 10, 1960, Ser. No. 14,041 1 Claim. (Cl. 57-555) This invention relates to drawtwisting machinery and more particularly to driving apparatus for drawtwisting machinery used in the textile industry of the type employed to stretch and twist filamentary material formed from such synthetic compositions as nylon and the like.

In present day textile practice, the processing of fila mentary material, particularly continuous filaments formed from synthetic material such as nylon, frequently includes an operation which is known as drawtwisting. In the drawtwisting operation continuous multifilamentary or monofilarnentary yarn or thread is drawn or stretched to orient the molecules in the filaments and impart tensile strength thereto and is then twisted.

In the drawtwisting machinery now in commercial use, the thread or yarn is passed over a feed roll and from the feed roll the yarn travels to a draw roll. From the draw roll the yarn or thread travels to a wind-up spindle with a ring and traveler assembly. The yarn is drawn between the feed roll and the draw roll and is twisted between the draw roll and the wind-up spindle. The draw roll is driven at a faster speed that the feed roll and the amount that the yarn is drawn or stretched depends upon the diiierence in speeds at which these two rolls are driven. The speed of the wind-up spindle, in relation to the delivery speed of the draw roll, controls the amount that the yarn is twisted. Thus, in order to control the drawtwisting operation, some means must be provided to control the speeds of the feed roll, the draw roll and the wind-up spindle to run in a predetermined synchronism.

The drawtwisters now in commercial use provide the necessary synchronism by driving all three elements from a single motor and providing the necessary speed diiferences by means of gearing and belting. These drawtwisters are limited in speed and performance because shaftwhip, gear back-lash, belt slippage and numerous other variables cause breakage of the yarn to become excessive as speed is increased. Maintenance on these drawtwisters is heavy because of the number of gears, belts, and brakes and other mechanical equipment which is subject to wear. Oil filled gear boxes require constant checking and refiling and the inevitable spillage creates a housekeeping problem.

.A commercial drawtwisting machine has a multiplicity of positions at each of which a separate drawtwisting operation is carried out. All of the positions are driven together by mechanical interconnections, and as a result some types of malfunctioning at a single position require that all of the positions he stopped. Thus, production is lost at all positions when only one position malfunctions.

Another drawback of the commercially available equipment is the limitations on the size of deniers which can be drawn. The size of deniers is limited by the size of the equipment necessary to transmit power to the end position of the drawtwisting machine.

The present invention provides a machine which is capable of drawing and twisting all commercially produced deniers of yarn at high rates of speed and with less breakage than is possible with the equipment of the prior art. Another feature of this invention is that it permits individual position control and thus eliminates the disadvantage of a production loss on all positions during the time when one position has to be shut down.

The drawtwister of the present invention comprises an individually motor driven feed roll, an individually motor driven draw roll and an individually motor driven windup spindle. The motors driving the feed roll and the draw roll are of the synchronous type and the motor driving the wind-up spindle is of the induction type. Since the motors driving the feed roll and the draw roll are. synchronous, their operating speeds are determined by the frequencies of the power supplies feeding these motors. The speeds of the draw roll and the feed roll are maintained at the desired predetermined values and relationship by supplying power of the correct frequencies to the synchronous motors driving these rolls. The load on the induction motor driving the wind-up spindle is light, and as a result, the speed of the induction motor will also be directly determined by the frequency of the induction motor power supply. The speed of the wind up spindle is maintained at the correct value and relationship with the speeds of the feed roll and the draw roll by supplying power of the correct frequency to the induction motor. The power supplies having the predetermined frequencies are generated by alternators, the output frequencies of which are selectively variable and can be precisely controlled.

The drawtwister of this invention, as described above, is capable of running yarn at many times the rates possible in the machinery of the prior art and can draw and twist deniers many times larger than can be drawn and twisted by any other commercial drawtwister presently available.

Further objects and advantages of the invention will become readily apparent as the following detailed description of the invention unfolds when taken in conjunction with the single figure of the drawings, which diagrammatically illustrates the drawtwister of the invention.

As shown in the figure, the yarn is designated by the reference numeral 11. The yarn 11 is initially packaged on a supply bobbin 12. The yarn 11 is unwound from the bobbin 12 and travels through a creel pigtail guide 13 and a snub guide 14. From the snubguide 14 the yarn 11 travels in a downward direction to a traverse bar and guide 15. At the traverse guide 15, the yarn 11 changes direction and moves upward from the traverse guide 15 over a top cot roll 16, which is mounted for pivotal movement by means of an arm 17. The arm 17 can move the top cot roll 16 selectively into engagement with a feed roll 18 as shown in the drawing. The yarn 11, after passing over the top cot roll 16, passes between the top cot roll and the feed roll 18 so that the yarn [11 is held between the rolls 16 and 18 as it advances through the drawtwister. From the feed roll 18, the yarn travels in a downward direction to draw pin 19. The yarn wraps around the draw pin 19 and then wraps several times around both a separator roll 20 and a draw roll 21. From the draw roll 21, the yarn travels downward through a balloon guide 22 to a ring and traveler assembly 23 of a well-known type and then is wound around the wind-up spindle 24 where it is packaged. The ring and traveler assembly 23 reciprocates vertically to distribute the yarn being wound around the wind-up spindle 24 The supply bobbin 12, the top cot roll 16, the draw pin 19, and the separator roll 20 are all mounted for free rotation. The feed roll 18 is driven by a synchronous motor 25, the draw roll 21 is driven by synchronous motor 26, and the wind-up spindle 24 is driven by an induction motor 27 by means of a tape drive 28. A1- ternators 29, 30 and 31 supply the A.C. power to the motors 25, 2.6 and 27, respectively. The speed of operation of each of the synchronous motors 25 and 26 depends directly upon the frequency of the AC. voltages applied thereto by the alternators 29 and 30, respectively. The output frequencies of the alternators 29 and 30 are selectively variable and precisely controllable, so that the speeds of the feed roll 18 and the draw roll 21 can be precisely selected and controlled. The motor 26 will be controlled to drive the draw roll 21 at a faster speed than the feed roll 18 and thus the yarn 11 will be drawn or stretched between the feed roll 18 and the draw roll 21. In this manner, the amount that the yarn is drawn can be precisely controlled and predetermined by the control of the frequencies generated by the alternators 29 and 30.

The wind-up spindle 24- presents a light load to the induction motor 27. As a result, the speed of the motor 27 will be directly determined by the frequency of the AC. signal applied to the motor 27 from the alternator 31. The output frequency from the alternator 31, like that of the alternators 29 and 30, is selectively variable and it can be precisely controlled. Thus the speed of the motor 27 can be controlled within the desired limits, and, therefore, the relationship between the speed of the spindle 24 and the speeds of the feed roll 18 and the draw roll 21 can be controlled within the desired limits. In operation, the speed of the spindle 24 will be selected to be faster than that of the draw roll 21. The relationship between the speeds of the draw roll 21 and the wind-up spindle 24 determine the amount of twist which is put in the yarn wound around the spindle 24. Thus, the drawing and twisting of the yarn 11 is selected and controlled within the desired limits by the selection of the output frequencies of the alternators 29, 30 and 31.

The drawtwister described above is capable of running yarn at up to 800 yards per minute and is capable of drawing and twisting deniers many times larger than can be processed by any other commercial drawtwister presently available.

The drawtwister disclosed in the drawing will be just one of a multiplicity of positions of a drawtwisting machine. The feed roll 18, the draw roll 21, and the windup spindle 24 in each position will be driven by different motors 25, 26 and 27, respectively. The AC. power to all the motors 25 will be supplied from the single alter nator 29. Likewise, the AC. power for the motors 26 and 27 will be supplied from the single alternators 30 and 31. Since each position is driven by a separate set of motors, one position can be shut down without shutting down all of the positions and thus valuable production time is saved.

The above description is of a preferred embodiment of the invention and many modifications may be made thereto without departing from the spirit and scope of the invention which is limited only as defined in the appended claims.

What is claimed is:

In a drawtwister having a feed roll, a draw roll, means to supply filamentary material to be drawn from said feed roll to said draw roll, means for twisting the drawn filamentary material, the improvement comprising a first synchronous motor connected to drive said feed roll, a second synchronous motor connected to drive said draw roll, an induction motor connected to drive said twisting means, first means to generate a selectively variable frequency voltage connected to supply power to said first synchronous motor, second means independent of said first means to generate a selectively variable frequency voltage connected to supply power to said second synchronous motor, and third means independent of said first means and said second means to generate a selectively variable frequency voltage connected to supply power to said induction motor.

References Cited in the file of this patent FOREIGN PATENTS 715,799 Great Britain Sept. 22, 1954 

